Revert "Revert "change minimum SDK to 9""
Revert "Revert "change minimum SDK to 9""

This reverts commit 3bf7e122b80aa06d038a3e213ca39ce580237c3c.

wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning,wasn-lab/visual-positioning